Prognostic value of 18F-fluorodeoxyglucose positron emission tomography in patients with small hepatocellular carcinoma treated by radiofrequency ablation.

Ida, Yoshiyuki; Tamai, Hideyuki; Shingaki, Naoki; Shimizu, Ryo; Maeshima, Shuya; Maekita, Takao; Iguchi, Mikitaka; Terada, Masaki; Kitano, Masayuki

BACKGROUND 18F-fluorodeoxyglucose (18F-FDG) uptake in hepatocellular carcinoma (HCC) is significantly associated with early recurrence and survival after curative surgical resection. However, there are no reports regarding the relationship between 18F-FDG uptake and outcomes after radiofrequency ablation (RFA). A prospective cohort study was conducted to evaluate the prognostic value of 18F-FDG positron emission tomography (PET) in HCC patients after RFA. METHODS A total of 121 consecutive patients with primary HCC (≤3 tumors, of diameter ≤ 3 cm) without vascular invasion on imaging were examined by 18F-FDG-PET computed tomography prior to RFA. An HCC with a component of 18F-FDG uptake visibly stronger than that of surrounding liver was defined as 18F-FDG-PET positive. RESULTS The median follow-up period was 1267 days. There were 110 18F-FDG-PET negative and 11 positive tumors. The cumulative 1-year recurrence rates in the 18F-FDG negative and positive groups were 30 and 64% (P = 0.017), respectively, and cumulative 1-year metastatic recurrence rates were 6 and 36% (P < 0.001), respectively. The cumulative 5-year survival rates were 88 and 22% (P < 0.001), respectively. Multivariate analysis revealed 18F-FDG-PET positivity and tumor size as independent factors related to metastatic recurrence and survival after RFA. CONCLUSIONS 18F-FDG-PET positivity was significantly associated with outcomes after RFA. RFA should not be readily selected as the first-line treatment for small HCC that includes a component of visually strong 18F-FDG uptake.